Increased sodium entry in H295R-S2 α7-5HT3-R cells stimulated aldosterone biosynthesis and induced apoptosis rather than proliferation, mimicking features of KCNJ5 mutations.
A novel cell model reveals that sodium influx-driven aldosterone biosynthesis is associated with apoptosis rather than proliferation, indicating additional factors are required for adenoma formation in primary aldosteronism.
BACKGROUND: Primary aldosteronism is the most common form of secondary hypertension. The most frequent genetic cause of aldosterone-producing adenomas is somatic mutations in the potassium channel KCNJ5. They affect the ion selectivity of the channel, with sodium influx leading to cell membrane depolarization and activation of calcium signaling, the major trigger for aldosterone biosynthesis. METHODS: To investigate how KCNJ5 mutations lead to the development of aldosterone-producing adenomas, we established an adrenocortical cell model in which sodium entry into the cells can be modulated on demand using chemogenetic tools H295R-S2 α7-5HT3-R (α7-5HT3 receptor) cells. We investigated their functional and molecular characteristics with regard to aldosterone biosynthesis and cell proliferation. RESULTS: A clonal cell line with stable expression of the chimeric α7-5HT3-R in H295R-S2 (human adrenocortical carcinoma cell line, Strain 2) cells was obtained. Increased sodium entry through α7-5HT3-R upon stimulation with uPSEM-817 (uPharmacologically Selective Effector Molecule-817) led to cell membrane depolarization, opening of voltage-gated Ca 2+ channels, and increased intracellular Ca 2+ concentrations, resulting in the stimulation of CYP11B2 expression and increased aldosterone biosynthesis. Increased intracellular sodium influx did not increase proliferation but rather induced apoptosis. RNA sequencing and steroidome analyses revealed unique profiles associated with Na + entry, with only partial overlap with Ang II (angiotensin II) or potassium-induced changes. CONCLUSIONS: H295R-S2 α7-5HT3-R cells are a new model reproducing the major features of cells harboring KCNJ5 mutations. Increased expression of CYP11B2 and stimulation of the mineralocorticoid biosynthesis pathway are associated with a decrease of cell proliferation and an increase of apoptosis, indicating that additional events may be required for the development of aldosterone-producing adenomas.
Fedlaoui et al. (Wed,) conducted a other in Primary aldosteronism. Modulation of sodium entry using chemogenetic tools (uPSEM-817) was evaluated on Aldosterone biosynthesis, cell proliferation, and apoptosis. Increased sodium entry in H295R-S2 α7-5HT3-R cells stimulated aldosterone biosynthesis and induced apoptosis rather than proliferation, mimicking features of KCNJ5 mutations.
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